If you want more traffic to your site or want to better understand what your market is looking for you should explore Wordtracker.
Query the association words of multiple foreign websites at once
A keyword research tool that generates thousands of profitable keywords with monthly search volume, CPC & competition
Free Keyword Tool for Amazon, Google, YouTube, eBay, Etsy, Walmart, and Bing search.
Query the real search results of Google keywords in various countries and regions, click to view
Use the latest Google search data to provide accurate and targeted advertising
Keywords hitter gives you all the keywords you should write about if you want to explore a topic.